Substituted 2-(2-hydroxyethyl)tetrahydro-1,4 oxazines and quaternary salts thereof useful for treating spasmodic syndromes

ABSTRACT

2-(2-Hydroxyethyl)tetrahydro-1,4-oxazines and quaternary salts thereof having the formula: ##STR1## WHEREIN Ar and Ar 1  are the same or different and are unsubstituted and substituted aryl, said substituent being a halogen atom, R represents a lower alkyl group having from 1 to 4 carbon atoms, R 1  is zero when X.sup.(-) is zero or is an alkyl group of from 1 to 4 carbon atoms which is the same or different from R, as defined above, and X.sup.(-) is zero when R 1  is zero or is selected from the group consisting of Cl.sup.(-), Br.sup.(-), I.sup.(-) and CH 3  SO 4 .sup.(-) when R 1  is lower alkyl, as defined above, is described. These compounds are useful for treating spasmodic syndromes.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to novel substituted 2-(2-hydroxyethyl)tetrahydro-1,4oxazines as well as to their quaternary derivatives useful in human therapeutics for the treatment of spasmodic syndromes. The invention relates also to a process for obtaining these compounds and to the application of said quaternary derivatives to the treatment of spasmodic syndromes of the smooth muscle.

2. Description of the Prior Art

A large number of aminoalchohol derivatives are known possessing spasmolytic properties (Ehrhart/Ruschig Arzneimittel II p. 75-97).

These spasmolytic properties are coupled either with an anticholinergic action or with a musculotropic action.

OBJECTS AND GENERAL DESCRIPTION OF THE INVENTION

The quaternary derivatives of the 2-(2-hydroxyethyl)tetrahydro-1,4 oxazines according to the present invention possess markedly and simultaneously both antichorlinergic and musculotropic actions. They correspond to the following general structural formula: ##STR2##

In this formula the substituents have the following significance:

Ar and Ar₁, which can be the same or different, represent aromatic residues, such as phenyl nuclei, which can be substituted by a halogen atom or unsubstituted;

R and R₁, can be the same or different, represent a lower alkyl group having 1 to 4 carbon atoms; and

X³¹ is an anion of the type Cl⁻, Br⁻, I⁻ or CH₃ SO₄ ⁻.

The present invention also relates to the substituted 2-(2-hydroxyethyl)tetrahydro-1,4 oxazines themselves, notably useful as intermediates in the synthesis of the compounds of formula IV.

The invention also relates to a process for producing these compounds.

The compounds according to the invention are synthesised from 2-cyanomethyl tetrahydro-1,4 oxazines whose preparation has been described by applicants in French patent application No 74 16 331 of 10 May 1974. These starting compounds correspond to the general formula: ##STR3## in which R has the same significance as indicated above. A derivative of this type can be easily converted by the action of HCl in an Et OH medium, then hydrolysed and treated with anhydrous NH₃, into the corresponding ester, passing through the intermediate stage of the imino-ester which is not necessary to isolate.

One of these esters is then reacted with at least one organomagnesium compound of the type Ar--MgX' or Ar₁ --MgX' in a solvent such as ethyl ether, Ar (or Ar₁) having the above-indicated significance and X' being a halogen atom.

The compounds thus obtained can serve as intermediates in syntheses. For example, it is possible to react them with a reactant of the type R₁ -X to obtain the corresponding quaternary ammonium salts, whose pharmacological properties justify their use in medicine for the treatment of spasmodic conditions.

The process of synthesis may be shown schematically as follows: ##STR4##

DESCRIPTION OF PREFERRED EMBODIMENTS

The invention is described in more detail in the following Examples, given purely by way of illustration and which are not to be regarded as defining the invention in any way.

EXAMPLE 1 ##STR5##

In a first step, 2-carbethoxy-methyl 4-methyl tetrahydro-1,4 oxazine of the formula ##STR6## is synthesised.

For this purpose:

70 g of 2-cyanomethyl tetrahydro-1,4 oxazine are dissolved in 1000 ml of absolute ethanol. This solution is saturated at -10° C with anhydrous HCl gas.

20 ml of water are then added and it is refluxed for 1 hour.

After having driven off the solvent, the residue is taken up with 400 ml of anhydrous chloroform and the solution is treated with a current of anhydrous NH₃.

The precipitated NH₄ Cl is filtered off. The solvent is distilled and the residue is rectified under vacuum, to obtain 52 g of the above ethyl ester.

BP₁₂ = 108° C

N_(D) ²³° = 1,4480

Under the usual conditions, a solution of phenylmagnesium bromide in anhydrous ethyl ether is prepared, from 7.2 g of magnesium turnings, 47.1 g (0.3 M) of bromobenzene and 100 ml of anhydrous ether. 18.7 g (0.1 M) of 2-carbethoxy-methyl 4-methyl tetra-hydro-1,4-oxazine are added with vigorous stirring, gradually, so as to keep the solvent refluxing. After the addition, refluxing is continued for 3 hours.

It is hydrolysed under the usual conditions with a saturated solution of NH₄ Cl. The decanted organic phase is extracted with an aqueous solution of ˜ 4N HCl. The aqueous solution is washed with ether then made alkaline with Na₂ CO₃. The product crystallises. After recrystallisation from anhydrous ether, 10.5 g of compound 1 are obtained.

MP = 110° C

Its hydrochloride, obtained by treating a solution of the base in absolute Et OH with anhydrous HCl gas, has a melting point MP = 212° C and has the following analytical characteristics:

    ______________________________________                                         (where M = 333.88)                                                                    C %      H %       N %       HC1 %                                      ______________________________________                                         Calculated                                                                              68.35      7.24      4.19    10.92                                    Found    68.14      7.26      4.13    10.91                                    ______________________________________                                    

EXAMPLE 2 ##STR7##

A solution of 5 g of Compound 1 in 50 ml of pure acetone is treated with 5 g of methyl bromide. After some hours, the product crystallises. After draining, it is recrystallised in absolute Et OH.

5 g of product are thus obtained.

MP = 233° C.

    ______________________________________                                         Analysis for M = 392.35                                                               C %      H %       N %       Br %                                       ______________________________________                                         Calculated                                                                              61.22      6.67      3.57    20.36                                    Found    61.31      6.73      3.41    19.93                                    ______________________________________                                    

EXAMPLE 3 ##STR8## 16 g of Compound 3 are obtained by operating under the same conditions as those described for compound 1, starting from 22.9 g (0.1 M) of 2-carbethoxy-methyl 4-n-butyl tetrahydro-1,4 oxazine, prepared as described in the Example 1, but replacing the absolute ethanol by n-butanol. Melting point of the hydrochloride MP = 211° C

    ______________________________________                                         Analysis of the hydrochloride                                                  (for M = 375.94)                                                                      C %      H %       N %       HC1 %                                      ______________________________________                                         Calculated                                                                              70.29      8.04      3.72    9.70                                     Found    71.00      7.97      3.63    9.64                                     ______________________________________                                    

EXAMPLE 4 ##STR9##

2 g of Compound 3 in 50 ml of pure acetone are treated with 2 g of methyl bromide. The cristals obtained are recrystallised from absolute EtOH.

In this way 2.5 g of Compound 4 are obtained.

MP = 244° C

    ______________________________________                                         Analysis (for M = 4.33.42)                                                               C %        H %     N %                                               ______________________________________                                         Calculated  63.74        7.21    3.23                                          Found       64.01        7.38    3.17                                          ______________________________________                                    

EXAMPLE 5 ##STR10##

5 g of the Compound 3 in 50 ml of acetone were treated with 2 g of freshly distilled methyl sulfate. After 12 hours the solvent was driven off. The residue was treated with ethyl acetate. 4.5 g of Compound 5 were thus obtained.

MP = 165° C.

    ______________________________________                                         Analysis (for M = 449.62)                                                                C %        H %     N %                                               ______________________________________                                         Calculated  61.44        7.85    3.11                                          Found       61.18        7.63    2.93                                          ______________________________________                                    

EXAMPLE 6 ##STR11##

Under similar conditions to those described in Example 1, from 7.2 g of magnesium, with 52.5 g (0.3 M) of 4-fluoro bromobenzene, 100 ml of anhydrous ether and 18.7 g of 2-carbethoxy-methyl 4-methyl tetrahydro-1,4 oxazine, 16.7 g of Compound 6 were obtained.

Melting point of the hydrochloride: 128° C (hygroscopic)

    ______________________________________                                         Analysis of the hydrochloride : (M = 369.85)                                          C %      H %       N %       HC1 %                                      ______________________________________                                         Calculated                                                                              61.70      5.99      3.79     9.86                                    Found    61.57      5.82      3.75     9.80                                    ______________________________________                                    

EXAMPLE 7 ##STR12##

5 g of the Compound 6 in 60 ml of pure acetone were treated with 4.5 g of methyl bromide. After recrystallisation in anhydrous isopropanol, 4.8 g of the product were obtained.

MP = 134° C (hygroscopic)

    ______________________________________                                         Analysis (M = 428.33)                                                                 C %      H %       N %       Br %                                       ______________________________________                                         Calculated                                                                              56.08      5.65      3.27    18.66                                    Found    56.15      5.62      3.13    19.00                                    ______________________________________                                    

Pharmacological tests

The pharmacological studies of the compounds according to the invention were directed essentially to the elucidation of the antispasmodic potentialities of the cations, particularly at the level of smooth muscle spasms induced by acetylcholine, histamine and Ba⁺⁺ ions. These investigations were carried out in vitro according to the technique of MAGNUS (Pflug. Arch. Ges. Physiol. 1904, 102, 349, and 1904, 103, 515 and 525) by using as biological indicators the jejunum of the rat for the first agonist and the ileum of the guinea pig for the two other agonists. The isolated organs were kept alive in a thermostatic oxygen Tyrode solution at 30° C and their contractions were recorded.

The response curve line as a function of the dose enabled the calculation of the affinity parameters (pA₂ and pD'₂) of the compounds according to the invention for the different types of receptor (VAN ROSSUM J.M. - Arch. Int. Pharmacodyn. 1963, 143, 299 -330).

The results obtained with the compounds according to the invention and two conventional compounds taken as references are given in Table I below:

                                      TABLE I                                      __________________________________________________________________________                                                TYPE OF                             AGONISTS       ACETYLCHOLINE                                                                              HISTAMINE                                                                              Ba.sup.++                                                                              ANTAGONIST                          COMPOUNDS      pA.sub.2                                                                             pD'.sub.2                                                                            pA.sub.2                                                                           pD'.sub.2                                                                          pA.sub.2                                                                           pD'.sub.2                                                                          EXERTED                             __________________________________________________________________________       2            6.7   --    5.20                                                                               --  4.90    Competitive                           7            5.46  3.21  5   3.70                                                                               5.87                                                                               4.04                                                                               Dualist                             Tiemonium      7     --    5.21                                                                               --  4.95                                                                               --  Competitive                         Papaverine     --    5.03  --  4.98                                                                               --  4.78                                                                               Non                                                                            competitive                         __________________________________________________________________________

These results interpreted by the principles of molecular pharmacology developed by ARIENS et Al. (Medicinal chemistry (Molecular pharmacology), 1, 119 - 286), show a great similarity of mechanism and intensity of action between compound no 2 and Tiemonium and for compound no 7 a mechanism of action which brings into play at the same time the competitive mechanism of Tiemonium and the non-competitive mechanism of papaverine.

To the knowledge of applicants, this dualism of activity is unknown for any other antispasmodic agent.

These pharmacological results therefore enable the application of these compounds to be envisaged in human therapeutics for the treatment of all spasmodic syndromes of the smooth muscle, whether of vascular, digestive or bronchial origin. The compounds could be administered in customary pharmaceutical forms at daily dosages comprised between 10 and 500 mg according to the route of administration, of the active compound. The active compound may be associated with the usual pharmaceutical excipients or vehicles for the provision of dosage units. 

We claim:
 1. A compound selected from the group consisting of 2-(2-hydroxyethyl)tetrahydro-1,4-oxazines of the formula: ##STR13## wherein Ar and Ar₁ are the same or different and are selected from the group consisting of unsubstituted and substituted aryl, said substituent being a halogen atom, R is lower alkyl having from 1 to 4 carbon atoms; and the quaternary salts thereof having the formula: ##STR14## wherein Ar, Ar₁ and R are as defined above and R₁ is lower alkyl having from 1 to 4 carbon atoms and X.sup.(-) is selected from the group consisting of Cl.sup.(-), Br.sup.(-), I.sup.(-) and CH₃ SO₄ (-).
 2. The compound of claim 1, wherein Ar and Ar₁ are identical and selected from the group consisting of C₆ H₅ and C₆ H₄ F.
 3. The compound of claim 1, wherein R is selected from the group consisting of CH₃ and C₄ H₉.
 4. The compound of claim 1, wherein Ar and Ar₁ are identical and are C₆ H₅ or C₆ H₄ F; R and R₁ are lower alkyl of 1 to 4 carbon atoms and X.sup.(-) is Cl.sup.(-), Br.sup.(-), I.sup.(-) or CH₃ SO₄.sup.(-).
 5. The compound of claim 4, wherein R is CH₃ or C₄ H₉.
 6. The compound of claim 4 wherein R₁ is CH₃.
 7. Pharmaceutical composition for the treatment of spasmodic syndromes, notably of the smooth muscle, comprising an anti-spasmolytic effective amount of a compound of claim 1 and a pharmaceutically acceptable carrier.
 8. A method of treating spasmodic syndromes, notably of the smooth muscle, comprising administering to a patient having said spasmodic syndromes a daily amount of from 10 to 500 mg of an antispasmolytic compound of claim
 1. 